Department of Molecular Biology, University of Duisburg-Essen, Essen, Germany.
Department of Neurosurgery, University of Duisburg-Essen, Essen, Germany.
J Neurochem. 2020 Sep;154(6):662-672. doi: 10.1111/jnc.14985. Epub 2020 Mar 13.
A major dose-limiting side effect of docetaxel chemotherapy is peripheral neuropathy. Patients' symptoms include pain, numbness, tingling and burning sensations, and motor weakness in the extremities. The molecular mechanism is currently not understood, and there are no treatments available. Previously, we have shown an association between neuropathy symptoms of patients treated with paclitaxel and the plasma levels of neurotoxic sphingolipids, the 1-deoxysphingolipids (1-deoxySL) (Kramer et al, FASEB J, 2015). 1-DeoxySL are produced when the first enzyme of the sphingolipid biosynthetic pathway, serine palmitoyltransferase (SPT), uses L-alanine as a substrate instead of its canonical amino acid substrate, L-serine. In the current investigation, we tested whether 1-deoxySL accumulate in the nervous system following systemic docetaxel treatment in mice. In dorsal root ganglia (DRG), we observed that docetaxel (45 mg/kg cumulative dose) significantly elevated the levels of 1-deoxySL and L-serine-derived ceramides, but not sphingosine-1-phosphate (S1P). S1P is a bioactive sphingolipid and a ligand for specific G-protein-coupled receptors. In the sciatic nerve, docetaxel decreased 1-deoxySL and ceramides. Moreover, we show that in primary DRG cultures, 1-deoxysphingosine produced neurite swellings that could be reversed with S1P. Our results demonstrate that docetaxel chemotherapy up-regulates sphingolipid metabolism in sensory neurons, leading to the accumulation of neurotoxic 1-deoxySL. We suggest that the neurotoxic effects of 1-deoxySL on axons can be reversed with S1P.
多西紫杉醇化疗的一个主要剂量限制的副作用是周围神经病。患者的症状包括疼痛、麻木、刺痛和烧灼感,以及四肢无力。目前尚不清楚其分子机制,也没有可用的治疗方法。以前,我们已经表明,接受紫杉醇治疗的患者的神经病变症状与血浆中神经毒性神经鞘脂,即 1-脱氧神经鞘脂(1-deoxySL)之间存在关联(Kramer 等人,FASEB J,2015 年)。当神经鞘脂生物合成途径的第一酶丝氨酸棕榈酰转移酶(SPT)将 L-丙氨酸用作底物而不是其典型的氨基酸底物 L-丝氨酸时,就会产生 1-脱氧 SL。在当前的研究中,我们测试了在小鼠全身多西紫杉醇治疗后,1-脱氧 SL 是否会在神经系统中积累。在背根神经节(DRG)中,我们观察到多西紫杉醇(45mg/kg 累积剂量)显著升高了 1-脱氧 SL 和由 L-丝氨酸衍生的神经酰胺的水平,但没有升高鞘氨醇-1-磷酸(S1P)的水平。S1P 是一种生物活性神经鞘脂,也是特定 G 蛋白偶联受体的配体。在坐骨神经中,多西紫杉醇降低了 1-脱氧 SL 和神经酰胺的水平。此外,我们还表明,在原代 DRG 培养物中,1-脱氧鞘氨醇产生的神经突肿胀可以用 S1P 逆转。我们的结果表明,多西紫杉醇化疗会使感觉神经元中的神经鞘脂代谢上调,导致神经毒性 1-脱氧 SL 的积累。我们建议,1-脱氧 SL 对轴突的神经毒性作用可以用 S1P 逆转。